SEOUL, South Korea (AP) — North Korea is threatening the U.S. and South Korea over joint naval drills taking place this week in tense Yellow Sea waters ahead of a Washington summit by the allies' leaders.

The North's Korean People's Army warning Tuesday was highly conditional. It said it will hit back if any shells fall in its territory. Should the allies respond to that, Pyongyang's military vows to strike five South Korean frontline islands.

While such language is standard, it comes at a time of tentative diplomatic maneuvering. Pyongyang had somewhat eased a tirade of threats aimed at larger-scale military drills by the allies that ended April 30.